Harvesting energy from small temperature differences

A new boost converter for low voltage input is presented. It is optimized for high efficiency at input voltages of few 10 mV. The developed prototype is operating at an input voltage of about 15 mV. A cold start needs about 36 mV. At 120 mV input and 3.6 V output an efficiency of more than 70% is reached. The developed booster is compared against commercial available boost converters in terms of efficiency, start-up voltage and costs. A test under real conditions has been done using a 30x30mm sized low-cost TEG. At a temperature difference of 3 K enough energy can be harvested to power an embedded system with a DC drive opening and closing a valve